Asymmetric Transmission in Diffractive Chiral Metasurfaces Consisting of Nanoantennas

Abstract

We have studied the asymmetric transmission in diffractive chiral metasurfacesconsisting of nanoantennas. The study was made of lattice plasmon modes on thephenomenon of asymmetric transmission in chiral two dimensional arrays ofplasmonic nanoparticles. It was demonstrated that asymmetric transmission resultedfrom contribution of higher order diffracted waves. It was shown that the isolatednanostructures has a fourfold rotational symmetry, the diffractive metasurfacesexhibited asymmetric transmission for normal incidence light within spectral range forwhich lattice plasmon modes were supported. It was found that lattice plasmon modesplayed role in enabling symmetric transmission in diffractive chiral metasurfaces. Thesymmetric transmission mechanism is due to different lattice plasmon mode excitationefficiencies of left circularly polarized and right circularly polarized and right circularlypolarized light. The excitation efficiencies are controlled by tailoring the nano particlesin plan distribution of scattered light for circularly polarized excitation and itsalignment with the inplane diffraction orders of the metasurfaces. The phenomenon fora metasurface composed of an array of a chiral nanoparticles consisting of fournanoantennas. It was shown that the Rayleigh anomaly condition where theasymmetric transmission effect was strongest and metasurfaces supported latticeplasmon modes. It was found that the difference in the inplane scattered intensityvaried as a function of the inplane angle around the nanostructure, rotating thenanostructure in the plane of the metasurface. The obtained results found in goodagreement with previously obtained results